259 
56 
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The Preparation 

and Use of Sweet Whey 

in Powder Form 



Address before the Medico-Chirurgical 
Society of Central New York at its 
Twenty-fourth Regular Meeting 
Syracuse, N. Y., December 5, 1907 



By LEWIS C. MERRELL 



Hall & McChesnev 

printers, bookbinders and blank book makers 

Syracuse, N. Y. 



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JAN 4 iy08 
Ooi»yri«M tiwy 

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Copyright 1907 
By Lewis C. Merrell 



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THE PREPARATION AND USE OF SWEET WHEY 
IN POWDER FORM 

BY LEWIS C. MERRELL 

In considering the many products which are produced from milk, 
such as milk sugar, casein, milk tiour, butter, cheese and condensed 
milk, it seems strange that one of the most valuable by-products of 
milk, namely whey, has never been preserved in permanent form. 

Whey contains very valuable food materials, but in a very dilute 
state. An average composition is that given b}' Konig as the re- 
sult of fortv-six analvses : 



.1- 



Fat o _ 

Proteid 0.86 

Sugar 4.79 

Salts 65 

Total Solids 6.62 

Water 93.38 

Eliminating the water, the solids show the following composition : 

Fat 4.83 

Proteid ^300 

Sugar 72.36 

Salts 9.81 

Practically speaking whey may be considered as milk from which 
the casein and most of the fat have been removed. It may be pro- 
duced in two ways, either by the action of a dilute acid, or by 
means of an enzyme, such as rennet or pepsin. If the whey is to 
be used for food purposes, rennet is usually employed, as it will act 
in neutral or slightly acid solutions, and may be used to produce a 
sweet whey. The addition of rennet to milk causes the casein to 
coagulate, carrying down with it the butter fat enmeshed. The 
whey separates from the curd as a clear yellowish liquor, sweet at 
first, but developing acidity rapidly. The proteid of the whey is 
largely lact-albumen. The carbohydrate is milk sugar, and the ash 
comprises the mineral matter of the milk. Rennet acts best at a 
temperature of 106° F (41° C). At this temperature, and for 
several degrees on either side, the curd produced is very firm ; at 
low temperatures, 15° to 20° C, the curd is quite soft, and wdien 
the temperature is raised to 50° C, the curd produced is also soft. 



4 THE PREPARATION AND USE OF SWEET WHEY IN POWDER FORM 

Whey usually contains some butter fat and more or. less small 
particles of curd depending on the temperature at which the ren- 
net action takes place and the care used in cutting the curd to free 
the whey. 

The value of whey as a modifier of milk or cream is accepted. 
It contains, as we have seen, all of the ingredients of fresh milk 
except the casein and fat. Its proteid is largely lact-albumen, 
which together with the milk sugar and mineral matter form a de- 
sirable adjuvant with which to properly balance the ingredients of 
cows' milk to produce a synthetic milk for the use of the infant. 

The ratio of albumen to casein in cows' milk is i to, perhaps, 4 (.)r 
5. '1 he ratio in human milk is i to, perhaps, i or 2. The de- 
sirability of increasing the lact-albumen of cows" milk in pro- 
portion to the casein by the addition of whey is at once apparent. 

Asa matter of fact fresh liquid whe\', in spite of its many ad- 
vantages, is but little used. For one thing it is not easy to prepare, 
for another it is rarely unifcn-m unless the greatest care be ex- 
ercised as to temperature and methods. It usually contains a vary- 
ing amount of coagulated curd in small particles. It must often be 
freshly prepared, as it sours rapidly. Last but not least, it con- 
tains so much water, 93;^ or more, that when mixed with milk or 
cream it forms a milk which is so dilute that it furnishes insufficient 
nourishment for any but very young infants. 

To put this a little more plainly, let me say that 15 ounces of 
whey contains approximately 14 ounces of water and i ounce of 
whey solids. Modified milks usually require 10 or 11 ounces of 
water to one ounce of whey solids in order to agree closely with 
human milk as regards the proportions of the different ingredients. 

Whey is quite frecpiently used as a food for adults on account of 
the ease with which it is assimilated. Liquid whey cannot however 
be used exclusively to nourish an adult on account of the large 
amount of water which would necessarily be ingested to secure the 
requisite amount of nourishment. 

It is quite evident that to fulfill its greatest usefulness whey 
should be prepared in the form of a permanent dry powder after 
the fashion of milk sugar so that it need only be dissolved to be 
ready for use. 

A little study of the history of milk preservation makes plain the 
reason why whey has not hitherto been thus prepared. It contains 
nearly all of the lact-albumen of the milk. This albumen coagulates 
at a comparatively low temperature and is rendered partially or 
wholly insoluble if an attempt be made to reduce or remove its 
water content by any process which necessitates the use of a 



THE PREPARATION AND USE OF SWEET WHEY IN POWDER FORM 5 

temperature above r6o° F. An illustration o£ this fact is found in 
the albumen of condensed milk which is considerably reduced in 
solubility by the sterilizing heat used to make the condensed milk 
keep. 

Whey is even more sensitive to heat than milk, for on account of 
its large milk sugar content, acidity developes rapidly and coagu- 
lates the albumen, a result which is even less desirable than that 
produced by too much heat. For this reason it is difficult to remove 
the moisture content of whey at a low temperature because a slow 
process would furnish ideal conditions for the development of 
sufficient acidity to coagulate the albumen. 

Many obstacles present themselves in the attempt to jDroduce a 
powdered sweet whey, but they are not insurmountable, as evidenced 
by the fact that the author has succeeded in ol)taining the solids of 
whey in the form of a dry powder without in any way altering the 
solubility of the albumen 

Some description of this process may prove of interest Sweet 
whole milk, selected for freshness and cpiality, is subjected to the 
action of rennet. The whey is separated from the curd as expedi- 
tiously as possible to avoid the development of acidity in the whey. 
The whey is then pasteurized just above 150° F. to destroy any 
rennet remaining, which might otherwise act upon milk or cream 
with which the whey might subsequently be mixed. The whey is 
then condensed in vacuo at a temperature below 135° F. to about 
one-fourth of its original bulk. The concentrated whey is then 
desiccated by projecting it in the form of a fine spray into a current 
of hot dry air. The licpiid particles are deprived of their moisture 
immediately, and fall like powdery snow. 

vStrange to say the current of drying air into which the sprayed 
material is projected may be very high in temperature, sav 300° F., 
without injuring the soluljility or life of the most delicate substances, 
that is to say without even producing pasteurization. At first glance 
this seems absurd. T will describe how this "air boiling" may be 
done. 

In the first place let me say that I have selected the term " air 
boiling" to distinguish this process from those in which the liquid 
is boiled by contact with heated metal. This process boils or 
evaporates the liquid by contact with heated air. If the liquid is 
boiled in a kettle, the steam has no way of escape except upward 
through the licjuid. Can you imagine what would happen if each 
particle of vaporous steam were greedily absorbed by the metal of 
the kettle as soon as formed? 

If a tiny drop of licjuid is suspended in heated air what happens? 



G THE PREPARATION AND USE OF SWEET WHEY IN POWDER FORM 

Evaporation proceeds on all, sides of. the little sphere, drawing heat 
from the center of the particle. On account of its spherical form 
the particle is really being cooled by the rapid evaporation of its 
moisture. Logically, the hotter the air current the more rapid the 
evaporation of the moisture, and the greater the cooling effect on 
the reinaining tiny mass of solids. Of course the air current itself 
is cooled somewhat by the evaporation in which it takes part, and, 
provided the temperature of the air is reduced below the point of 
combustion, no harm results from this temporary exposure to heat, 
and a state of dryness is produced which protects and preserves the 
tiny particles of material. 

The solids of fresh whey evaporated by this process appear under 
the microscope as amorphous semi-transparent quartz-like masses. 
The powder is instantly soluble in water, hot or cold, and nothing 
settles out of solution. In fact upon examination, the fluid cannot 
be distinguished from fresh whey. 

The efficiency of this drying is best understood when I say that 
I have produced materials containing less than half of one per cent 
of moisture. Two per cent is the least amount of moisture found 
in materials dried by any other process with which I am familiar; 
and ten to fourteen per cent is not uncommon. 

The keeping quality of dried organic matter depends largely on 
its moisture content, and the author is in a position to say that 
materials of this nature do not keep well if the moisture content 
runs much above three and one-half per cent. 

Chemical change is inhibited by this extreme dryness, and I can 
say from personal observation that such powders (hermetically 
sealed) may be exposed to any temperature below the point of 
combustion without injury. Albumen dried in this way is not 
coagulated by a temperature of 212° F, and I should deduce from 
this fact, that the presence of water in certain quantity is essential 
to coagulate albumen by heat. 

To illustrate the delicacy with which this process will remove 
moisture from organic matter without injury, I will say that I have 
dried such materials as yeast, diastase, pepsin and certain forms of 
beneficial bacteria to less than 2 per cent moisture content without 
impairing their strength, preserving them for two years or more 
hermetically sealed, and find them unimpaired in vitality on add- 
ing water. This extreme dryness can therefore be produced with- 
out injuring the most delicate organic substances and is effective in 
preserving them from deterioration. 

The process lends itself with equal facility toward producing 
powders from fresh eggs, milk and cream. This egg powder has 



THE PREPARATION AND USE OF SWEET WHEY IN POWDER FORM 7 

been used for some time by the- United States Navy, and the Navy 
Department has inchided seven tons of it as well as a considerable 
amount of Vv^hole milk powder in the supplies for the Pacific Fleet 
which sails on December 15. The powder made from whole milk 
has been used for some time by one of the largest Soldiers' Homes 
in the United States. This is restored with water and served as 
fresh milk for drinking purposes for the veterans, and the oiificer in 
charge prefers it to the local supply of fresh milk, which is of 
questionable origin. 

To return to the subject of whey, I should like to compare the 
powder with some of the materials commonly used either as com- 
plete foods or as milk modifiers. 

There are two classes of such materials — those to be used with 
water and those to be used with milk. Most of the latter require 
cooking, and contain a considerable percentage of insoluble car- 
bohydrates, usually from 35 to So^'^, there being only two foods of 
this class whose carbohydrates are entirely soluble. 

The chief value of all cereal foods is their power of attenuating 
the curd of cows' milk. It is well known that whey also possesses 
the power of producing an exceedingly fine coagulum when di- 
gested with milk or cream, and in fact nothing else will produce 
equal results unless perhaps barley water. This characteristic is 
retained by the powdered whey and must be due either to the 
albumen or the ash, for I do not know that any one has ever 
claimed any attenuating power for milk sugar which is so often 
used to modify milk. 

Among the foods intended to be used with water probably the 
most prominent are malted milk and nestle's milk food. I desire 
to compare these tw^o products with the powdered sweet whey. 

malted miller nestle milk food^ whey powder 

Moisture 2.55 2.18 1.20 

Fat 1. 41 4-45 -27 

Proteids 14.00 10.72 14—5 

Soluble carbohydrates 63-87 43- 84 74-45 

Insoluble carbohydrates i5-68 35 34 None 

Ash 3.57 1.60 9.80 

p Bui. 59 Laboratory of the Inland Rev. Department, Canada. 

On examining these analyses we find that the powdered whey 
contains more proteid than either of the others. This proteid is 
mostly lact-albumen and is entirely soluble, whereas the proteids 
of the other two are only partially soluble. 

We also find that the whey has no insoluble carbohydrates, and 
a much higher percentage of soluble carbohydrates than either of 



8 THE PREPARATION AND USE OF SWEET WHEY IN POWDER FORM 

the Others, and this carbohydrate- is milk sugar. It is also very 
much richer in ash than the others, and it is safe to assume that 
the ash of whey is very desirable in promoting the growth of bones 
and teeth. 

It has been suggested to me that a large proportion of the diges- 
tive troubles of young infants are caused, directly or indirectly, by 
difficult or deferred cutting of the teeth. If this should prove to 
be the case, the use of a whey powder containing a considerable 
amount of milk ash might be of great value.' 

The amount of fat in all these products is so small that it should 
be disregarded. A loor' solution of any one of them would contain 
less than half of W of fat. This is about as close as a centrifugal 
separator wmII skim milk, and w^e are not in the habit of consider- 
ing that skimmed milk contains any fat. 

My reason for showing this comparative table is to illustrate the 
fact that powdered sweet whey dissolved in water is a much more 
desirable food for adults or infants than either of the other products 
above mentioned. You will note that the ratio between the pro- 
teids and carbohydrates in w'hey powder is about i to 5J4', which is 
well above the accepted nutritive ratio of i to 6 or 7. 

Probably the best method of using whey powder is to prepare it 
with Avater and cream. The ci'eam is low in casein, sugar and ash, 
but high in fat. The whey is low in fat, but high in ash, sugar and 
albumen, which the cream lacks. The fact that the whey is dry 
makes the arrangement of percentages comparatively easy and the 
number of modifications is practically infinite. 

As an illustration of the way in which mixtures containing any 
desired proportions of fat, proteid and carbohydrate may be pro- 
duced by the use of cream and whey powder, I have prepared a 
few formulae for 20-ounce mixtures. This quantity is easily divided 
or increased so as to give any desired amount of modified milk. 
For instance one-half of the ingredients given makes a lo-ounce 
mixture; one-quarter more of the ingredients makes 25 ounces ; 
and one-half more makes 30 ounces. 

I have assumed that the upper 4 ounces from a quart bottle of 
milk contains 20^ fat, and that the upper 11 ounces contains lofc fat. 
One ounce of 20^ cream in a 20-ounce mixture represents i.oof^ of fat, 
o. 15^ proteid and o. 2ofo milk sugar. One ounce of lofc cream in a 20- 
ounce mixture represents 0.50?^ of fat, 0.16,^ of proteid and 0.20^ of 
sugar. Two ounces of milk represents 0.40^ fat, 0.35^ proteid and 
0.45^ sugar. One dram of sweet whey powder represents o.io^^ 
proteid and 0.50;^ milk sugar. It will bs evident tliat if any or all 
of these ingredients are placed together in a graduate glass, and 



THE PREPARATION AND USE OF SWEET WHEY IN POWDER FORM 9 

water added so that the total quantity equals 20 ounces, the relative 
proportions of fat, proteid and sugar represented by the percentage 
given will be maintained. 

A suitable mixture for a child three months of age might be pre- 
pared as follows : 

3 ounces of 20;;^ cream This represents t^ of fat, .45,^ 

proteid and .6f^ milk sugar. 
II drams of whey powder This represents i.ifo proteid and 
Lime water (if desired) k^.z^';/c sugar. 

When water has been added to make the total quantity 20 ounces 
there will be 3^ fat, 1.55;^ proteid and 6.i'/c milk sugar. 

For a child 10 months of age the following formula might be 
utilized: 

8 ounces 10;, cream This represents j^'fo fat, 1.28^ pro- 

teid and 1.60^ sugar. 
I ^' ounces of whey powder This represents \'fc proteid and 
Lime water (if desired) 5^ sugar. 

When sufficient water has been added to make the quantity up to 
20 ounces we have 4^ fat, 2.28^ proteid and 6.68^ milk sugar. 

A very desirable formula for adults might be constructed as 
follows : 

20 ounces milk This represents 4% fat, 3.5;^,' pro- 

teid and 4.5^^ milk sugar. 

I ounce of whey powder This represents .2>fc proteid and 4^ 

milk sugar. 

The finished mixture would have a total of 4^ fat, 4.30^ proteid 
and 8.50^ milk sugar. In this case it would not be necessary to add 
any water. Milk inodified in this way w^ould contain about ly;^ of 
solids, which is about half as much again as cows' milk usually 
contains. In this way a very nourishing food is produced which 
does not require the ingestion of so great an amount of water to 
secure complete nourishment as if milk alone has been used. 

We have seen from the foregoing that a powdered whey may be 
used in two ways, either as a modifier of milk and cream or as a com- 
plete food in itself. The fact that it is a natural product, and that 
its ingredients practically do not differ in character from their 
original condition in fresh milk, makes the material especially de- 
sirable from an ethical standpoint. The methods used in its 
manufacture are in nowise secret, and the utility of whey is so well 
known that it is unnecessary to make any extraordinary claims as 
to the beneficial results it will produce in cases where its use is in- 
dicated. 



10 THE PREPARATION AND USE OF SWEET WHEY IN POWDER FORM 

I wish to say that whey _ produced by the processes usually em- 
ployed in making" cheese is not suitable for nutritive purposes. 

The milk is, as a rule, handled less carefully than that used for 
domestic consumption or for making butter or condensed milk, for 
the cheesemaker can add a culture of lactic bacteria (commonly 
called starter) and induce a vigorous growth of lactic bacteria which 
will kill off any other germ life which the milk may contain. Both 
the acidity and the lactic bacteria are very necessary to the ripen- 
ing of the cheese curd but their presence is not compatible with 
the production of a sweet whey. 

Whey manufactvired for nutritive purposes must be prepared 
from the best and freshest inilk from inspected dairies, and must 
be cpiickly and carefully treated by laboratory methods under com- 
petent superintendence, to produce a sweet and uniform whey in 
the form of a powder. 

NOTE: Its proteids (whej-) consist almost entirely of lactalbumin, with a very small propor- 
tion of lactoglobiilin, and perhaps other soluble proteids in minute quantities. These bodies col- 
lectively have been termed the whey-proteids by White and Ladd. The terra, however, is rather 
awkward, and, since lactaDiumin forms almost the entire proteid content of the whey, it .seems 
best to speak of the whey-proteids specifically as lactalbumin, and as such the term will be here- 
after used.— Thom^^son S. Weafcoff. M. D., Instructor in Diseases of Cliihlren, University of 
Pennsylvania. The American Journal of Medical Sciences, Oct., IDOl. 



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